Guaranteed to survive just 90 days, the Mars rovers are thriving, giving hope to scientists that more discovery lies ahead.
Now might have seemed the perfect time for an epitaph. One year ago this week, the first of NASA's two Martian rovers came to rest on the desolate fields of the Red Planet, the clock already ticking on a life span guaranteed to last only 90 days.
But since that moment, Spirit and its later-arriving twin, Opportunity, have written in soil and stone the scenes that scientists since the Renaissance had only been able to imagine. While one spun its way across two miles of Martian desert and then 200 feet up a rock-strewn hillside in an unprecedented feat of interplanetary engineering, the other looked into the telltale squiggles of ancient rocks and proved that a lake of liquid water once covered the wide, dark expanse of the Meridiani plain.
The rovers have exceeded not only the greatest hopes of the scientific world, but also their own life expectancy - and they are still going. Somewhat unexpectedly, on this first anniversary, there is as much reason to look forward as backward.
As Spirit scrambles toward the top of its barren hilltop, there are rocks that tell a still-misunderstood story, perhaps hinting at an ancient Martian flood. And half a world away, beyond plains that stretch featureless and gray to every horizon, a bizarre landscape of bare rock and corduroy dunes awaits Opportunity.
"We've mentally adapted ourselves to the idea that these rovers can go on and on," says Joy Crisp, a project scientist at the Jet Propulsion Laboratory in Pasadena, Calif., which runs the mission. "Potentially, it could be many months."